Is it possible to use a shared spi bus for addressable led’s connected in parallel?

A

Apa102

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Is it possible to use a shared bus for the clock and data lines on the Apa102’s in parallel rather than in series

I’m using individual bare apa102 dotstars that are not in a strip in an atypical arrangement. I would like to use as few wires to connect to each dotstar and was wondering if I could use them WITHOUT a cable leaving the data out and clock out lines.

I would like to connect them in parallel using a shared data line and a shared clock line each going into only the data IN and clock IN of each pixel. This is so that instead of using Data In, Clock In, Power, Ground, Data Out, Clock out lines which is a total of 6 cables attached to each pixel, I would only be using four: Data In, Clock In, Ground and Power.

Would each pixel be able to function the same way as they would when the data out of one pixel is connected to the data in of the next pixel? 9A5AB69F-4BFF-49B0-9367-203C4A3EB0F6.jpg
 
Apa102 said:
Would each pixel be able to function the same way as they would when the data out of one pixel is connected to the data in of the next pixel?View attachment 29724
Click to expand...
No. Since your topology is parallel, all connected dotstars will receive the same SPI data and thus display the same color.
So also this blog about how data is transferred through a string of dotstars.

Paul
 
7DFD3858-563E-48DB-96C3-5AD99A77FA67.jpg
PaulS said:
No. Since your topology is parallel, all connected dotstars will receive the same SPI data and thus display the same color.
So also this blog about how data is transferred through a string of dotstars.

Paul
Click to expand...

Would this arrangement work? It would be a waste of extra dotstars but to control the top two pixels, I would send data to their counterpart on the bottom? As in the top dotstar would receive the same data as the first pixel on the bottom and both would show the same color, and again the second top pixel would receive the same as the second pixel on the bottom and also share the same color?
 
Yes, yes and yes to your questions. The left 2 dotstars will show the same color and the right 2 dotstars will show the same color.

Paul
 
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